1 files changed, 158 insertions, 6 deletions

diff --git a/OpenSim/Framework/TaskInventoryDictionary.cs b/OpenSim/Framework/TaskInventoryDictionary.cs
index 421bd5d..814758a 100644
--- a/OpenSim/Framework/TaskInventoryDictionary.cs
+++ b/OpenSim/Framework/TaskInventoryDictionary.cs
@@ -27,9 +27,13 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
+using System.Reflection;
 using System.Xml;
+using System.Diagnostics;
 using System.Xml.Schema;
 using System.Xml.Serialization;
+using log4net;
 using OpenMetaverse;
 
 namespace OpenSim.Framework
@@ -45,6 +49,155 @@ namespace OpenSim.Framework
         // private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
         private static XmlSerializer tiiSerializer = new XmlSerializer(typeof (TaskInventoryItem));
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        
+        private Thread LockedByThread;
+        private string WriterStack;
+
+        private Dictionary<Thread, string> ReadLockers =
+                new Dictionary<Thread, string>();
+
+        /// <value>
+        /// An advanced lock for inventory data
+        /// </value>
+        private System.Threading.ReaderWriterLockSlim m_itemLock = new System.Threading.ReaderWriterLockSlim();
+
+        /// <summary>
+        /// Are we readlocked by the calling thread?
+        /// </summary>
+        public bool IsReadLockedByMe()
+        {
+            if (m_itemLock.RecursiveReadCount > 0)
+            {
+                return true;
+            }
+            else
+            {
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Lock our inventory list for reading (many can read, one can write)
+        /// </summary>
+        public void LockItemsForRead(bool locked)
+        {
+            if (locked)
+            {
+                if (m_itemLock.IsWriteLockHeld && LockedByThread != null)
+                {
+                    if (!LockedByThread.IsAlive)
+                    {
+                        //Locked by dead thread, reset.
+                        m_itemLock = new System.Threading.ReaderWriterLockSlim(); 
+                    }
+                }
+
+                if (m_itemLock.RecursiveReadCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive read lock requested. This should not happen and means something needs to be fixed. For now though, it's safe to continue.");
+                    try
+                    {
+                        StackTrace stackTrace = new StackTrace();           // get call stack
+                        StackFrame[] stackFrames = stackTrace.GetFrames();  // get method calls (frames)
+
+                        // write call stack method names
+                        foreach (StackFrame stackFrame in stackFrames)
+                        {
+                            m_log.Error("[SceneObjectGroup.m_parts]  "+(stackFrame.GetMethod().Name));   // write method name
+                        }
+                    }
+                    catch
+                    {}
+                    m_itemLock.ExitReadLock();
+                }
+                if (m_itemLock.RecursiveWriteCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive write lock requested. This should not happen and means something needs to be fixed.");
+                    m_itemLock.ExitWriteLock();
+                }
+                
+                while (!m_itemLock.TryEnterReadLock(60000))
+                {
+                    m_log.Error("Thread lock detected while trying to aquire READ lock in TaskInventoryDictionary. Locked by thread " + LockedByThread.Name + ". I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+                    if (m_itemLock.IsWriteLockHeld)
+                    {
+                        m_itemLock = new System.Threading.ReaderWriterLockSlim();
+                        System.Console.WriteLine("------------------------------------------");
+                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+                        System.Console.WriteLine("------------------------------------------");
+                        System.Console.WriteLine("Locker's call stack:\n" + WriterStack);
+                        System.Console.WriteLine("------------------------------------------");
+                        LockedByThread = null;
+                        ReadLockers.Clear();
+                    }
+                }
+            }
+            else
+            {
+                if (m_itemLock.RecursiveReadCount>0)
+                {
+                    m_itemLock.ExitReadLock();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Lock our inventory list for writing (many can read, one can write)
+        /// </summary>
+        public void LockItemsForWrite(bool locked)
+        {
+            if (locked)
+            {
+                //Enter a write lock, wait indefinately for one to open.
+                if (m_itemLock.RecursiveReadCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive read lock requested. This should not happen and means something needs to be fixed. For now though, it's safe to continue.");
+                    m_itemLock.ExitReadLock();
+                }
+                if (m_itemLock.RecursiveWriteCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive write lock requested. This should not happen and means something needs to be fixed.");
+                    m_itemLock.ExitWriteLock();
+                }
+                while (!m_itemLock.TryEnterWriteLock(60000))
+                {
+                    if (m_itemLock.IsWriteLockHeld)
+                    {
+                        m_log.Error("Thread lock detected while trying to aquire WRITE lock in TaskInventoryDictionary. Locked by thread " + LockedByThread.Name + ". I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+                        System.Console.WriteLine("------------------------------------------");
+                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+                        System.Console.WriteLine("------------------------------------------");
+                        System.Console.WriteLine("Locker's call stack:\n" + WriterStack);
+                        System.Console.WriteLine("------------------------------------------");
+                    }
+                    else
+                    {
+                        m_log.Error("Thread lock detected while trying to aquire WRITE lock in TaskInventoryDictionary. Locked by a reader. I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+                        System.Console.WriteLine("------------------------------------------");
+                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+                        System.Console.WriteLine("------------------------------------------");
+                        foreach (KeyValuePair<Thread, string> kvp in ReadLockers)
+                        {
+                            System.Console.WriteLine("Locker name {0} call stack:\n" + kvp.Value, kvp.Key.Name);
+                            System.Console.WriteLine("------------------------------------------");
+                        }
+                    }
+                    m_itemLock = new System.Threading.ReaderWriterLockSlim();
+                    ReadLockers.Clear();
+                }
+
+                LockedByThread = Thread.CurrentThread;
+                WriterStack = Environment.StackTrace;
+            }
+            else
+            {
+                if (m_itemLock.RecursiveWriteCount > 0)
+                {
+                    m_itemLock.ExitWriteLock();
+                }
+            }
+        }
 
         #region ICloneable Members
 
@@ -52,14 +205,13 @@ namespace OpenSim.Framework
         {
             TaskInventoryDictionary clone = new TaskInventoryDictionary();
 
-            lock (this)
+            m_itemLock.EnterReadLock();
+            foreach (UUID uuid in Keys)
             {
-                foreach (UUID uuid in Keys)
-                {
-                    clone.Add(uuid, (TaskInventoryItem) this[uuid].Clone());
-                }
+                clone.Add(uuid, (TaskInventoryItem) this[uuid].Clone());
             }
-            
+            m_itemLock.ExitReadLock();
+
             return clone;
         }